Influence of geometrical factors on steam ejector performance – A numerical assessment

Varga, Szabolcs; Oliveira, Armando C.; Diaconu, Bogdan

doi:10.1016/j.ijrefrig.2009.05.009

Cited by 152 publications

(58 citation statements)

References 25 publications

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“…Eames et al [14] confirmed that the nozzle exit position (NXP) and primary nozzle geometry had a strong influence on the entrainment performance. Varga et al [15] and Rusly et al [16] also observed that the position of the nozzle was an important design parameter, and the nozzle exit position affected the critical back pressure considerably.…”

Section: Introductionmentioning

confidence: 99%

Reverse Circulation Drilling Method Based on a Supersonic Nozzle for Dust Control

Yin

et al. 2016

Applied Sciences

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Abstract:To reduce dust generated from drilling processes, a reverse circulation drilling method based on a supersonic nozzle is proposed. The suction performance is evaluated by the entrainment ratio. A series of preliminary laboratory experiments based on orthogonal experimental design were conducted to test the suction performance and reveal the main factors. Computational fluid dynamics (CFD) were conducted to thoroughly understand the interaction mechanism of the flows. The Schlieren technique was further carried out to reveal the flow characteristic of the nozzle. The results show that the supersonic nozzle can significantly improve the reverse circulation effect. A high entrainment ratio up to 0.76 was achieved, which implied strong suction performance. The CFD results agreed well with experimental data with a maximum difference of 17%. This work presents the great potential for supersonic nozzles and reverse circulation in dust control, which is significant to protect the envrionment and people's health.

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Section: Introductionmentioning

confidence: 99%

Reverse Circulation Drilling Method Based on a Supersonic Nozzle for Dust Control

Yin

et al. 2016

Applied Sciences

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“…The co-efficient of the performance of ERS is directly proportional to the entrainment ratio of the ejector (Ruangtrakoon et al 2011). The geometry and the operating conditions of the ejector influence the entrainment ratio (Varga et al 2009). The effect of operating conditions on the performance of the ejector is relatively well established when compared with the geometrical effects (Ruangtrakoon et al 2013;Varga et al 2009;Sankarlal & Mani, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The geometry and the operating conditions of the ejector influence the entrainment ratio (Varga et al 2009). The effect of operating conditions on the performance of the ejector is relatively well established when compared with the geometrical effects (Ruangtrakoon et al 2013;Varga et al 2009;Sankarlal & Mani, 2005). The most influencing geometrical parameters over the performance of ejector are the area ratio (ratio of the area between constant area mixing chamber to primary nozzle throat), the primary nozzle exit position, the convergent angle of the constant pressure mixing section, and the length of constant area mixing section (Eames et al 2007;Jia & Wenjian, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Aphornratana and Eames (1997) initially assumed the NXP as 0.5 to 1.0 times the mixing chamber diameter and then studied various positions and concluded the optimum position as 0 to 0.833 times the mixing chamber's throat diameter. Varga et al (2009) has assumed the value of NXP according to the ejector manufacturer's recommendation. Zhang et al (2012) observed a good entrainment ratio while the value of NXP is 1.5 times of the mixing chamber diameter.…”

Section: Introductionmentioning

confidence: 99%

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Analytical and Numerical Studies of a Steam Ejector on the Effect of Nozzle Exit Position and Suction Chamber Angle to Fluid Flow and System Performance

Ramesh¹,

Sekhar²

2017

JAFM

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Nozzle exit position [NXP] plays a vital role in the performance of the ejector, but its values are specified in a range for the required operating condition. In this study instead of the range of values, a specific value, named as entrainment diameter is developed and its effect on the performance of the ejector is studied for several combinations of suction chamber angle using numerical method. The effect of the condenser and boiler pressures on the performance of the ejector are also studied to ensure the off-design operating conditions. The entrainment diameter of an ejector is derived analytically by solving one dimensional compressible fluid flow equations using MATLAB. To study the effect of entrainment diameter on the performance of the ejector, CFD technique is employed. Analytical and numerical results are validated with experimental data available in the previous studies. For 7 kW refrigeration capacity, it is inferred that the suction chamber angle of 18° and the corresponding entrainment diameter 90.8 mm with the NXP of 23.62 mm yield the maximum entrainment ratio. The study predicts that the performance of the ejector is highly influenced by the pressure increment at the exit of the nozzle, while the suction chamber angle is between 12° to 21°.

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“…For these reasons, ejector refrigeration systems can be used in buildings, in distributed tri-generation systems and for the waste heat recover from industrial processes (Ben Mansour et al, 2014;Godefroy et al, 2007;Little and Garimella, 2011). Nevertheless, the ejector refrigeration has not been able to penetrate the market because of the low coefficient of performance (Sarkar, 2012): this is because the efficiency of the whole system is highly influenced by ejector performances, which significantly depends on the geometry, working fluid and operating conditions (Kasperski and Gil, 2014;Selvaraju and Mani, 2006;Varga et al, 2009a;Yapıcı et al, 2008). This paper deals with the screening of the working fluids, using a validated lumped parameter model, in the range of operating conditions of low grade energy sources (waste heat and solar energy sources).…”

Section: Introductionmentioning

confidence: 99%

A study of working fluids for heat driven ejector refrigeration using lumped parameter models

Besagni

Mereu

Leo

et al. 2015

International Journal of Refrigeration

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COP Entrainment ratio Ejector refrigeration Ejector efficiencies a b s t r a c tThis paper studies the influence of working fluids over the performance of heat driven ejector refrigeration systems performance by using a lumped parameter model. The model used has been selected after a comparison of different models with a set of experimental data available in the literature. The effect of generator, evaporator and condenser temperature over the entrainment ratio and the COP has been investigated for different working fluids in the typical operating conditions of low grade energy sources. The results show a growth in performance (the entrainment ratio and the COP) with a rise in the generator and evaporator temperature and a decrease in the condenser temperature. The working fluids have a great impact on the ejector performance and each refrigerant has its own range of operating conditions. R134a is found to be suitable for low generator temperature (70e100 C), whereas the hydrocarbons R600 is suitable for medium generator temperatures (100e130 C) and R601 for high generator temperatures (130e180 C). i n t e r n a t i o n a l j o u r n a l o f r e f r i g e r a t i o n 5 8 ( 2 0 1 5 ) 1 5 4 e1 7

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Influence of geometrical factors on steam ejector performance – A numerical assessment

Cited by 152 publications

References 25 publications

Reverse Circulation Drilling Method Based on a Supersonic Nozzle for Dust Control

Reverse Circulation Drilling Method Based on a Supersonic Nozzle for Dust Control

Analytical and Numerical Studies of a Steam Ejector on the Effect of Nozzle Exit Position and Suction Chamber Angle to Fluid Flow and System Performance

A study of working fluids for heat driven ejector refrigeration using lumped parameter models

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